Directional antenna system



May 25, 1948; w. .1. POLYDOROFF DIRECTIONAL ANTENNA SYSTEM Original Filed June 14, 1945 3mm W Patented May 25, 1948 w S AT ES PATENT OFFICE tjife eet l-12.33.93 4; I

of the above' application is directed to I. iRl9m ni i ro d law n a s an ap nt p t cularl a l ca l t recep- Qt Pp efi lei t pne fiam W re ,inssu h instances *when'crossed-loops canbe employedto advantage. I he above patent as well as U. S. Patent No.

2f 36 l e cfipesqtbe a anta es. der from use of ferr c-magnetic loop antenna," via,

limit of pickup; by said; antenna because of thefpresenceof magnetic substances, improveinent indirectivity when suchloops are used for 'Za I99n.1P? ]W9 Tk relat v eas 'of s i din of such antenna, and general'reduction in size of the installation which makes it particularly adaptable for aircraft and marine navigational purposes.

" 'Ifhis'"invention willbe better understood if I referenceismade to the accompanying drawings lj; liCh'f 1..f Fl g.i;1"'shows pne construction of loopantennas nl' i Q m nfferljorma fltlc co I cults adaptableitoi faconstruction' of' Fig. 1

3'shows' the "assembly of the completed apparatus Refei'rifigjnowitoIfig; 1 two loops, i and 2 are shown," eacnwoundaround thec'ylinder, '4." The cylinder made "off ferro-ma'gnetic powdered material and-composed ofseveral toroidal rings assembled togetheftdform fa cylinder.

M s ina'y'b 'oiffaperibdic (low impedance dc pl'edindividuallytocirouits 6 and i of hroughconventional closed type transformers. l'.n ithis"ca'se, the circuits are so connec'te'd that the o'utpnt'is'eompared by means of a suitable indigatingmeteror by a cathode ray 119599995 In some cases it Ifiaybemuna convenient to compare two signals while they are brought in phase. Either of the receiver's may be precede-:1 or succeeded by an adjustable network to correctth'e hase of one of the signals before their outputs 'jcompar'ed'or combined in the oscil- .l'o's'cop'e. w 'Ihe'l construction OfFlgIfl may be advanta ous appli'ed'to'system where two loops are atright anglessuchasslrownin Fig. land the outputisfed intotwo'fix'ed windings and a movable search coil the rotation of which indicates the direction of a transmitter.

In this construction the loops are of low impedance type and are connected to a suitable receiver. The rotation of the search coil pros 2j andj 2a'sh'ow arrangement 'of the 'cird-uces maximum and minimum signals in the receiver. Care should be takenthat two windings are'placed in non-inductive'relation for which purpose one of the windings can be adjusted separately until 'no reaction exists between the windings; To avoid any capacitive coupling between the two windings each loop 0011' may be independently shielded.

Actual experience indicates that iron core greatly facilitate the positioning of two loops for the purpose of eliminating this reaction between two windings.

'Fig. 1 also provides another application of the invention whereby a'l'oop' winding I isused for directionalpurposesand is wound around a cylinder core 4. Around the cylinder another loop 2 is Wound so that its axisis perpendicular. to the axis of the first loopl In many instancesof direction fiinding the loop ismade rotatable to observe the zero reading after which in order to determine the sense of the direction the loop is turned degrees from its zero setting, at which latter position a vertical antenna is'applied'(9'0 degrees out of phase) 50 as to produce well known cardioid pattern by which the sense of the direction is found. To avoid this unnecessary delay in taking of two bearings, the second loop is switched in'lieu of the first loopyand its usual figurea pattern is transformed into a cardioid by an' addition at a vertical antenna to get a sense of the station. Thus by a simple selection of either loop and an addition of a vertical antenna the direction and sense are found atthe same position of a rotatable assembly.

It is evident that for successful operation of such system both loops should be' of the same inductance 'andwhilefi'rst loop should be shielded for a clean zero indication the second loop may be wound'over'the shield of the first loop, if the shield of the first loop is of the type known as Faraday screen and made of awire cloth in which allthe shielding wires run in one direction without completing loops. In certain instancessuch as on airplane installations it is possible to leave one of the loops unshielded and to enclose the assembly into a streamlined dome as shown on Fig.3. Experience shows that a domeof plastic material with metallized strips, l5, forms an effective Faraday screen. From the standpoint of precipitation static such a screen is particularly effective against such static when the screening strips are laid horizontally, i. e., at the right angle to the loops of Fig. 1; When loop assembly is rotatable inside of such dome, no appreciable change of inductance is noticed, as the incomplete loops of screening are at right angles metallizing process which produces semi-con ductive surfaces; by laying semi-"conductive substances on the surface to be screened; and by electro-deposit of thin layer of metal. Each compressed finely divided magnetic particles, screening means around said coil antenna, said screening means being formed by a plurality of co-axial open loops in the plane at right angle to the plane of said coil antenna and an elongated streamlined housing surrounding said antenna and said'screeningmeans.

3. An antenna system for two-directional reception of electro-magnetic radiations comprising a pair of coil antennas at right angle to each other wound around sides of a cylindrical ferromagnetic core-, said core being made in sections of compressed finely divided magnetic particles, screening means around at least one of said coil antenna-s switching means between said coil antnn'as' 'tdselect' one or the other and an elon screening turn may be considered completedthrough the capacity and therefore acts as an absorber of the horizontal component of the electro-magnetio radiations which is usually present at the frequencies above 1 m. c. and is particularly pronounced at night, therefore being known as night efi'ecti Thus the present. invention describes the novel ways of utilizing loop'coils around a commonmagnetic mass and new methods of applying such loops for directional purposes."

In the above described figures ferro-magnetic cores are shown in the shape of hollow cylinders but the. inventionis not limited to such shapes as it can be advantageously applied to any other shapes of cores; for instance, rectangular, spherical or any other symmetrical body of rotation.

Same type of loop with streamlined housing may beplaced on the roof of an automobile since at that position of the loop the ignition noises picked up by the loop will be negligible and another loo'p'a't right angle, when switched on, will enable to pick up the signals which happen to be in the direction of the travel; or means for slight misalignment of the loop from its original position may be provided, so .as to eliminate zero position. "1 The application is a' division of my co-pending application SerialNo. 490,941,- filed' on June 14, 1943, and entitled Directional antenna systems, now Patent 2,399,382, issued April 30, 1946, which was filed as continuation in part of U. S. Patent No. 2,339,234.

The'irivention is not to be limited to or by details or construction of the particular embodimerit thereof" illustrated by the drawings, as various'otlier forms of the device will of course be apparent to those skilled in the art Without departing from the spirit of the invention or the scope of the claims.

What I claim is: 1

1. Alow impedance antenna system for the reception of electro-magnetic radiations comprising a coil antenna wound in a vertical plane around the sides of a cylindrical core, said core beingmade in toroidal sections and composed of compressed finely divided magnetic particles, screening means around said coil antenna and an elongated streamlined housing in the shape of a dome surrounding saidantenna and said screenmg means.

2. A rotatable antenna system for directional reception of' electro-magnetic radiations comprising a coil antenna wound in a vertical plane around a fend-magnetic core in a form of a body of rotation, said core being composed of gatedlstreainlined housing surrounding said antenna and said screening means.

. 45A directional system for the reception of electro-magnetic radiations comprising a coil antenna wound in a vertical plane around a ferromagnetic core, said core made of toroidal sections to form a cylinder, each sectionbeing made of compressed finely divided'magnetic particles screening meansfin close relation 'to saidcoil antenna and anelongated streamlined houising having semi-conductive outside surface, said housing-surrounding said-coil antenna and said screeningmeans'. f, d

5. A V rotatable low impedance -directional antenna system for the reception of electro magnetic radiation comprising a coil antenna wound in a vertical plane around a ferro-magnetic core made. in the form of a body or rotation with screening means around saidflcoil antennaand an elongated streamlined dome housing, surrounding said antenna system and said screening means.. A

6. A rotatable low impedance directional antenna system for the reception of an electro inagnetic radiation comprising a coil antenn-awound in a vertical plane around. a ferroemagnetic core made in the, form. of abodyv of rotation, screening means surrounding said coil, antenna and an elongated streamlined dome housing around said system, said housing, having afsemiconducting outside surface.

7. A low impedance directional antenna systern for thelreception ofelectro-magneticradiation comprising a coil antenna wound in a. vertical plane and around a periphery cfaferro-magnetic core in the. form of a body of rotation, said core comprisingjtoroidal.sections and made of compressed finely divided magnetic particles and an elongated streamlined. housing in the shape of a dome having. a semi-conductive outside surface.

WLADI'MIR J. PQLYDOROFEQ REFERENCES 0min f The following references are of record in the file of this patent: i a

' Ul lITED s'r-A rEs PATENTS Number" Name .Date

2,266,262 Polydoroff Dec. 16, 1941 2,282,030 Busignies May 5, 1942 2,297,466 Funke et a1 Sept. 29,1942 2,316,623 Roberts Apr. 13, 1943 2,343,306 Lear Mal. 7,1944

Kreager Dec. 11, 1945 

